Offloaded KV Cache (#31325)

* Initial implementation of OffloadedCache

* enable usage via cache_implementation

* Address feedback, add tests, remove legacy methods.

* Remove flash-attn, discover synchronization bugs, fix bugs

* Prevent usage in CPU only mode

* Add a section about offloaded KV cache to the docs

* Fix typos in docs

* Clarifications and better explanation of streams
This commit is contained in:
Nikos Karampatziakis
2024-08-01 05:42:07 -07:00
committed by GitHub
parent b4727a1216
commit ca59d6f77c
4 changed files with 241 additions and 0 deletions

View File

@@ -38,6 +38,7 @@ if is_torch_available():
AutoModelForCausalLM,
AutoTokenizer,
DynamicCache,
GenerationConfig,
GPT2LMHeadModel,
LlamaConfig,
SinkCache,
@@ -513,3 +514,54 @@ class CacheIntegrationTest(unittest.TestCase):
@unittest.skip(reason="TODO @gante static cache's does not support beam search yet")
def test_static_cache_beam_search(self):
pass
@require_torch_gpu
def test_offloaded_cache_equivalent_to_dynamic_cache(self):
"""Tests that OffloadedCache produces the same result as the default DynamicCache"""
model_name = "microsoft/Phi-3-mini-4k-instruct"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(model_name, device_map="auto", torch_dtype=torch.float16)
device = model.device
input_text = "Fun fact:"
inputs = tokenizer(input_text, return_tensors="pt").to(device)
common = {
"num_beams": 4,
"num_beam_groups": 2,
"num_return_sequences": 4,
"diversity_penalty": 1.0,
"max_new_tokens": 20,
"early_stopping": True,
}
original = GenerationConfig(**common)
offloaded = GenerationConfig(cache_implementation="offloaded", **common)
original_outputs = model.generate(generation_config=original, **inputs)
offloaded_outputs = model.generate(generation_config=offloaded, **inputs)
for original_output, offloaded_output in zip(original_outputs, offloaded_outputs):
assert torch.all(original_output == offloaded_output).item()
@require_torch_gpu
def test_offloaded_cache_uses_less_memory_than_dynamic_cache(self):
"""Tests that OffloadedCache uses less memory than the default DynamicCache"""
model_name = "microsoft/Phi-3-mini-4k-instruct"
tokenizer = AutoTokenizer.from_pretrained(model_name)
model = AutoModelForCausalLM.from_pretrained(model_name, device_map="auto", torch_dtype=torch.float16)
device = model.device
input_text = "Fun fact:"
inputs = tokenizer(input_text, return_tensors="pt").to(device)
common = {
"num_beams": 4,
"num_beam_groups": 2,
"num_return_sequences": 4,
"diversity_penalty": 1.0,
"max_new_tokens": 20,
"early_stopping": True,
}
original = GenerationConfig(**common)
offloaded = GenerationConfig(cache_implementation="offloaded", **common)
torch.cuda.reset_peak_memory_stats(device)
model.generate(generation_config=original, **inputs)
original_peak_memory = torch.cuda.max_memory_allocated(device)
torch.cuda.reset_peak_memory_stats(device)
model.generate(generation_config=offloaded, **inputs)
offloaded_peak_memory = torch.cuda.max_memory_allocated(device)
assert offloaded_peak_memory < original_peak_memory